1. Technical Field of the Invention
The present invention relates to a cosmetic and/or dermatological composition more particularly intended for artificially tanning and/or browning the skin and comprising, in a cosmetically acceptable support, at least one derivative or a mixture of derivatives of 1,7-bisphenyl heptane-3,5-dione of particular structure and at least one self-tanning agent.
The present invention also relates to a cosmetic treatment process for artificially tanning or browning the skin and to the use of at least one derivative or a mixture of derivatives of 1,7-bisphenyl heptane-3,5-dione of particular structure for improving the coloration and/or stability of a self-tanning agent.
The invention also relates to the uses of these compositions for giving the skin a coloration close to that of a natural skin tan.
For the purposes of the present patent application, the term “self-tanning agent” means an agent which, when applied to the skin, especially to the face, gives a tanning effect that is more or less similar in appearance to that which may result from prolonged exposure to sunlight (natural tan) or under a UV lamp.
2. Description of the Prior Art
Nowadays, it is important to have a healthy appearance and tanned skin is always a sign of good health. However, natural tanning is not always desirable since it requires prolonged exposure to UV radiation, in particular to UV-A radiation which causes tanning of the skin, but on the other hand is liable to induce reactions or even impairment of the skin, especially in the case of sensitive skin or skin that is continually exposed to solar radiation: erythema, burns, loss of elasticity, appearance of wrinkles, premature aging. It is thus desirable to find an alternative to natural tanning, which is compatible with the requirements of such skin.
Most of the cosmetic products intended for artificially tanning the skin are based on carbonyl derivatives allowing, by interaction with the amino acids of the skin, the formation of colored products, among which mention is made of mono- or polycarbonyl compounds such as, for example, isatin, alloxan, ninhydrin, glyceraldehyde, mesotartaric aldehyde, glutaraldehyde, erythrulose and dihydroxyacetone (DHA).
DHA is a particularly advantageous product that is commonly used in cosmetics as an agent for artificially tanning the skin; when applied to the skin, especially to the face, it gives a tanning or browning effect that is similar in appearance to that which may result from prolonged exposure to sunlight (natural tanning) or under a UV lamp.
One drawback of DHA is the slow speed at which the coloration develops: in point of fact, it takes several hours (3 to 5 hours in general) for the coloration to be developed. The intensity of the coloration obtained on the skin and/or its staying power over time (resistance to washing) and/or the speed at which the coloration develops are often considered insufficient by the users of DHA-based self-tanning compositions.
Another problem posed by DHA-based compositions is that they have the annoying tendency, which is more or less pronounced depending on the nature of the medium in which they are formulated, of degrading over time. These problems associated with the storage and/or conservation of DHA-based compositions are generally reflected in the end by an undesirable yellowing of these compositions.
There is thus increasing demand for fast-acting self-tanning products that give a coloration close to that of a natural tan.